Technological advances in computer hardware, software and networking have lead to efficient, cost effective computing systems (e.g., desktop computers, laptops, handhelds, cellular telephones, servers, etc) that can provide inferences about future activities and/or occurrences. These systems continue to evolve into more reliable, robust and user-friendly systems. Oftentimes, pervasive computing applications that provide inferences about future activities can utilize data about the past; thus, such applications can be limited by their reliance on the limits of a current data set.
In a traditional closed-world approach to learning from data, current data points in a current data set can be considered as the basis for inferences. For example, a closed-world system designed to predict probability distribution over a person's current destination while the person is traveling, based on such observations of the time of day of the travel, and on the progression of the current trip, is conventionally limited to considering prior locations seen to be visited in a log of tours. Limitations in a database can have several sources. For instance, data collection can be costly in many research and application projects. Further, a lack of ongoing embedded sensing (which can be especially prevalent during early prototyping efforts) can mitigate an amount of time during which data can be collected. Also, privacy concerns may lead to access to only small windows of data. Moreover, even always-on monitoring systems can be associated with incompleteness as previously unobserved data can continue to be observed. According to an example, a person's destinations can be logged for an extended period of time, yet the person can continue to visit places that she has not been observed to have visited before. These previously unobserved places can be locations that the person did not visit during monitoring, yet had traveled to prior to such monitoring. Additionally or alternatively, the traveler may have never before visited these previously unobserved places. Thus, conventional techniques that generate predictions about a user's current or future activity can yield inaccurate results.